Does slightly deformed tip of bullet affect ballistics under 100 yards? - Page 2

**44 AMP** · January 9, 2019, 05:51 PM

hmmm, let's see...

take a rifle bullet at 3,000fps...
and, to make it easy lets say 1 in 12" twist..
so that's 1 turn per foot, and 3,000 feet per second x 60 seconds in a minute..

I get 180,000 rpm, rotational speed

Somebody else can tell us how that compares with a power drill, or the compressor vanes in a turbocharger..or jet engine...

Sounds really fast, to me, but is it?

zeke · January 9, 2019, 06:08 PM

maybe 30 revolutions at 100 yds? Never was real good at math when younger, and much older now

HiBC · January 9, 2019, 09:35 PM

It is pretty high rpm,but the answer s right in front of us. Every thing slows down,but one turn in 12 inches ? Is one turn in 12 inches. Or 3 per yard....

Sort of dampers the theory of the spinning bullet buzz sawing the insides of a critter.If nothing slowed down,the bullet would make about 1 1/4 turns passing through a deer.

**Mike Irwin** · January 10, 2019, 08:40 AM

To expand on my comments, I'm trying to find the photos that I've seen over the years of bullets in flight showing how the "atmosphere" for lack of a better word, flows around a bullet.

Essentially, a high velocity bullet's nose is in a fairly static bubble as it flies, meaning that it really has very little effect on the bullet's path.

The best photos that I've found are on the Wikipedia page on external ballistics.

This one, in particular, shows both the bow shock wave and the trailing turbulence path from the bullet's base.

https://en.wikipedia.org/wiki/Extern...llet,_1888.jpg

In the images I've seen where bullet bases are imperfect, the trailing turbulence path is a LOT more confused and decidedly not symmetrical.

briandg · January 10, 2019, 10:41 AM

I was always pretty good at math. By using my skills with physics and other disciplines, I can say with absolute confidence that a bullet that was fired from a rifle with a 1;12 twist, travelling at pretty much any realistic velocity will rotate 100 times at 100 feet, and 300 times at 300 feet.

The information shared here has been great.

To address the buzz saw effect, almost anyone here has seen gel tests. Myself, I've never seen any one of them with a buzz saw, whenever I have seen evidence of rotation, it's been one rotation in the block, just as it would be in flight.

But we are talking about accuracy, and just offhand, I think that mike has provided the best information as well as links to pages that can confirm it and provide further information.

Don Fischer · January 10, 2019, 11:07 AM

Something to think about. Year's ago Speer brought out the mag tip bullet. The idea was that the tip of a bullet melts off soon in flight. They had a high speed photo of it happening to sell their idea. If that is true then banged up bullet's don't hurt a thing. I think we can go even farther back than the mag tip and see the Rem core lock.Not much exposed tip on it either and it's a great bullet. On the other hand seem's I read somewhere that the plastic tip protect's the tip of the bullet. Probably does but better at starting opening I would think. Not sure the tip below the jacket need's protecting.

zeke · January 10, 2019, 11:16 AM

Guys-Thanks My math skills are not good. Also excellent link.

T. O'Heir · January 10, 2019, 11:32 AM

The only part of the bullet that matters is the base. If the base is damaged, in any way, the gases go in odd directions. That throws accuracy off.
Makes no difference what the point looks like. Think in terms or the plethora of point shapes. All of 'em are accurate.

Gas Bag · January 22, 2019, 02:31 PM

IMHO, no it doesn't. The deformity is too small to mean much.

January 9, 2019, 05:51 PM	#26
44 AMP Staff Join Date: March 11, 2006 Location: Upper US Posts: 28,839	hmmm, let's see... take a rifle bullet at 3,000fps... and, to make it easy lets say 1 in 12" twist.. so that's 1 turn per foot, and 3,000 feet per second x 60 seconds in a minute.. I get 180,000 rpm, rotational speed Somebody else can tell us how that compares with a power drill, or the compressor vanes in a turbocharger..or jet engine... Sounds really fast, to me, but is it? __________________ All else being equal (and it almost never is) bigger bullets tend to work better.

January 10, 2019, 08:40 AM	#29
Mike Irwin Staff Join Date: April 13, 2000 Location: Northern Virginia Posts: 41,390	To expand on my comments, I'm trying to find the photos that I've seen over the years of bullets in flight showing how the "atmosphere" for lack of a better word, flows around a bullet. Essentially, a high velocity bullet's nose is in a fairly static bubble as it flies, meaning that it really has very little effect on the bullet's path. The best photos that I've found are on the Wikipedia page on external ballistics. This one, in particular, shows both the bow shock wave and the trailing turbulence path from the bullet's base. https://en.wikipedia.org/wiki/Extern...llet,_1888.jpg In the images I've seen where bullet bases are imperfect, the trailing turbulence path is a LOT more confused and decidedly not symmetrical. __________________ "The gift which I am sending you is called a dog, and is in fact the most precious and valuable possession of mankind" -Theodorus Gaza Baby Jesus cries when the fat redneck doesn't have military-grade firepower.

January 10, 2019, 10:41 AM	#30
briandg Senior Member Join Date: May 4, 2010 Posts: 5,468	I was always pretty good at math. By using my skills with physics and other disciplines, I can say with absolute confidence that a bullet that was fired from a rifle with a 1;12 twist, travelling at pretty much any realistic velocity will rotate 100 times at 100 feet, and 300 times at 300 feet. The information shared here has been great. To address the buzz saw effect, almost anyone here has seen gel tests. Myself, I've never seen any one of them with a buzz saw, whenever I have seen evidence of rotation, it's been one rotation in the block, just as it would be in flight. But we are talking about accuracy, and just offhand, I think that mike has provided the best information as well as links to pages that can confirm it and provide further information. __________________ None.

January 10, 2019, 11:32 AM	#33
T. O'Heir Senior Member Join Date: February 13, 2002 Location: Canada Posts: 12,453	The only part of the bullet that matters is the base. If the base is damaged, in any way, the gases go in odd directions. That throws accuracy off. Makes no difference what the point looks like. Think in terms or the plethora of point shapes. All of 'em are accurate. __________________ Spelling and grammar count!

January 9, 2019, 06:08 PM	#27
zeke Senior Member Join Date: November 17, 1999 Location: NW Wi Posts: 1,671	maybe 30 revolutions at 100 yds? Never was real good at math when younger, and much older now

January 9, 2019, 09:35 PM	#28
HiBC Senior Member Join Date: November 13, 2006 Posts: 8,287	It is pretty high rpm,but the answer s right in front of us. Every thing slows down,but one turn in 12 inches ? Is one turn in 12 inches. Or 3 per yard.... Sort of dampers the theory of the spinning bullet buzz sawing the insides of a critter.If nothing slowed down,the bullet would make about 1 1/4 turns passing through a deer.

January 10, 2019, 11:07 AM	#31
Don Fischer Senior Member Join Date: March 2, 2017 Posts: 1,868	Something to think about. Year's ago Speer brought out the mag tip bullet. The idea was that the tip of a bullet melts off soon in flight. They had a high speed photo of it happening to sell their idea. If that is true then banged up bullet's don't hurt a thing. I think we can go even farther back than the mag tip and see the Rem core lock.Not much exposed tip on it either and it's a great bullet. On the other hand seem's I read somewhere that the plastic tip protect's the tip of the bullet. Probably does but better at starting opening I would think. Not sure the tip below the jacket need's protecting.

January 10, 2019, 11:16 AM	#32
zeke Senior Member Join Date: November 17, 1999 Location: NW Wi Posts: 1,671	Guys-Thanks My math skills are not good. Also excellent link.

January 22, 2019, 02:31 PM	#34
Gas Bag Member Join Date: January 3, 2019 Posts: 69	IMHO, no it doesn't. The deformity is too small to mean much.